Abstract

On an industrial robot positioning accuracy is important factor but there is not the standard method of calibration for robot dimensions that influence the positioning accuracy. This paper presents the calibration methods of SCARA type robot which has two linked arms move in plane. For calibration of robot dimensions, three points calibration method and four points calibration method have been developed. These methods are available for every SCARA type robots. On these methods robot dimensions are calibrated accurately by teaching function of robot with simple measuring instruments of robot tool point. In this paper a digitizer is used. The accuracy is almost equal to that of measuring instrument. The fact is verified in experimental results, and the accuracy of measured arm length is ±0.1 mm, that is the accuracy of digitizer used for calibration. These methods are based on the vector expression of robot model, so similar calibration method is available for the other type robot.